On the number of square integrable solutions and self-adjointness of symmetric first order systems of differential equations

Matthias Lesch, Mark M. Malamud

The main purpose of this paper is to investigate the formal deficiency indices ${\mathcal{N}}_{\pm }(I)$ of a symmetric first order system $$J{f}^{\prime }+Bf=\lambda \mathcal{H}f$$ on an interval $I$, wh…